Due to the nature of a mobile radio communications network, such as a cellular network, there often arises a requirement for a mobile terminal device such as so-called User Equipment mobile phone handset to change its operational connectivity, whether due to a handover between cells and/or a handover between networks and related communication systems.
In view of the variety of communication systems, and in particular legacy communication systems, that are in existence, to optimise connectivity and to minimize limiting effects on handset terminal performance, functionality allowing movement between different systems can provide particular advantageous.